Suppression of a Recoil Component in Ramsey Fringe Spectroscopy

Abstract

This chapter discusses the suppression of a recoil component in Ramsey fringe spectroscopy. In high resolution saturation spectroscopy, the recoil splitting leads to difficulty in determining the center of the transition because of extra broadening and line asymmetry. On the contrary, if both components are resolved, the height of the saturation dips will be significantly reduced and their line profiles will be distorted by second order Doppler broadening. The chapter presents a novel method to suppress the low frequency recoil component. The suppression of one recoil component could be demonstrated directly with Ramsey excitation. The confusing overlapping structures of the Ramsey interference fringes of both recoil components can be reduced to that of the high frequency component alone by removing the 3 P 1 population after the second interaction. With only one recoil component, the influences of the recoil effect, the second order Doppler effect, and the Ramsey fringe structure can be separated allowing a precise realization of the line center.